Motor drive circuits compare the potential in an RS resistance connected to an H-bridge circuit using comparators, and control the output current flowing into a coil of the motor by controlling the H-bridge circuit by PWM (Pulse Width Modulation) control based on the comparison result.
However, the potential in the RS resistance, when in the decay mode is a negative potential, and a zero point detection is implemented by comparing this potential with ground voltage. In addition, it is desirable to omit the RS resistance so that the number of parts can be reduced.